The Sputnik-3 was developed and built by OKB-1 (now RSC Energia) and was actually the first satellite that was really prepared for scientific work. Sputnik-1 was developed with the purpose of sending an object into outer space, whereas Sputnik-2 was designed in a hurry — to celebrate the anniversary of the October Revolution. «Satellite-3» was also much bigger and had a large number of various instruments. It was equipped with a tape recorder for recording telemetry, experimental solar panels, a beacon powered by the solar panels, as well as sensors for detection of cosmic rays, radiation, sunlight etc.
The launch of Sputnik-3 was held on May 15, 1958, using the modified R-7 rocket: to send the payload mass of 1327 kg into space the engineers had to build an additional missile unit. The satellite went successfully on an elongated elliptical orbit and remained there until April 6, 1960. As a result of the «Sputnik-3» mission, there were plans to create a whole family of similar devices.